UV Exposure Unit

FotoDave@aol.com
Thu, 30 Oct 1997 15:25:27 -0500 (EST)

I might be buying a used exposure unit. It has black light bulbs in it. The
exposing area is 24x18. The bulbs is 2-ft long, and there are 4 of them in
the unit, so the spacing is quite large (about 4 inches apart?)

The question is, if I am willing to sacrifice a little bit on exposure time
and place the paper further away (I think the way it is set up, the paper
will be about 4-5 inches from the tube), will that give even exposure? I
assume it should be because it was designed as an exposure unit.

Is exposure time going to be extremely long? Does inverse square law
approximately apply here? I remember there was a long discussion last year,
but I just need an approximate. Do you think with 4-5 inches distance (and
four 20W bulbs), will it take under or over 30 minutes to expose a gum print?

Also, the black-light tubes is 20W each. If I need UV tubes, I can simply
replace them by 20W UV tubes, correct?

Thanks a lot in advance for your help!

Dave